Post on 28-Jul-2015
transcript
Everybody look at your right index finger
Friction ridge analysis
Batman Ballistics
By chemically removing your fingerprints, you become virtually undetectable.
A. TrueB. FalseC. You’ve been watching too
much “Without a Trace”
History of Fingerprints
● Ancient Babylon, China, Persia
● 1686 - Malpighi○ notes ridges, spirals,
and loops● 1823 - Purkinje
○ names 9 patterns● 1958 - Hershel
○ utilized a handprint on a contract
○ criminal database
● 1880 - Faulds○ published in Nature
declaring fingerprints as means of personal identification
● Bertillon○ first scientific method
of identification● 1890 - Galton
○ publishes first book on fingerprints
History of Fingerprints
Faulds sends his paper to Darwin
Darwin sends Faulds’ paper to
Galton
Galton is credited with proving Faulds’ claims
Galton trained under Vucetich
Vucetich made the first criminal fingerprint
identification in 1892
Faulds’ claims:1. No two
fingerprints are exactly the same
2. Fingerprints do not change over the course of a person’s life
Rojas Murders
Anthropometry/Bertillionage
Defined: the study of human body measurements to be used for classification and measurement
● in the 19th and 20th centuries, it was used to classify criminals
● made famous by Alphonse Bertillon
Biometrics: use of measurements of portions of complex patterns from the human body to build a database that can be used to “verify” the “identity” of persons within that database
it worked until it didn’t
Will West
William West
fingerprints
Fingerprints
Latent prints:friction ridge impressions that are not visible to the unaided eye; consist of a mixture of natural secretions (98-99% sweat, oil)
patent prints: impressions of friction ridges which are visible to the unaided eye in media such as oil, blood, ink, or mud
Friction Ridges● Swellings on the fingertips begin
at 6.5 weeks● Shape of the volar pad and
resulting ridge patterns are due to genetics, physical influences and stresses in the womb
● At about 10-13 weeks, ridge patterns begin to develop. Volar pads begin to reduce in size until their boundaries and the surrounding skin merge
Friction Ridges
● The ridge arrangement on every hand and foot of every person is different
● What makes friction ridge patterns useful?○ Permanence and
Uniqueness
Anatomy of a scar
Can you alter your fingerprints?
in the 1930s, John Dillinger put acid on his fingertips but did
not destroy his ridges completely.in most cases, the act of alteration makes the prints
easier to identify by adding cuts/scars
to the ridge structure.
Friction Ridges
● definitively develop on fetus pre-birth
● persistent during life except for permanent scarring
● details are unique and never repeated
● overall patterns may vary within limits allowing for classification
Fingerprints
Classification System
inclusionexclusionCLASS
characteristics
Fingerprints
Identification: matching points of minutiae
INDIVIDUAL characteristics
Minutiae: features of the friction ridge skin patterns on fingertips that make the overall pattern individual
Points of minutiae
INDIVIDUAL characteristics
Minutiae diagram:a and b: Bifurcationsc: Enclosured and e: Ending ridgesf: Island(Reprinted from Galton (1892))
Points of minutiae
INDIVIDUAL characteristics
It is possible to recover a print from the sticky side of
duct tape.
A. TrueB. FalseC. You’ve been watching too
much NCIS
Video: Developing latent fingerprints on the adhesive sides of tape
Fingerprint Processing1. Visual
Examination or Search
2. Enhancement or
Visualization
3. Photography
4. Lifting or collection of
object 5. Laboratory analysis or comparison
Chemical Enhancements for Fingerprints
Cyanoacrylate(that’s superglue)● prints are fumed
with cyanoacrylate● then powdered to
visualize
Chemical Enhancements for Fingerprints
Ninhydrin● sprayed on latent
prints● heated to visualize
Which provides a macroscopic perspective?
A. Alternate Light source (ALS)
B. Magnifying glass
Which is a class characteristic?
A. BifurcationB. Whorl
Which type of print is visible without any additional enhancement or aid?
A. latentB. patent
Identification
Scientific Method
Identification depends on pattern matching points of minutia
Analysis - evaluate Level 1, 2, & 3 minutiaeComparison - determine agreement and discrepanciesEvaluation - cyclical procedure of evaluationVerification - 2nd examiner
ACE-V is the fingerprint discipline’s scientific method
Fingerprints
skin
slippage
Recovery of prints from deceased victim
Recovery of prints from deceased victim
Levels of Detail
Level 1:general ridge flow
and pattern configuration
Level 2:ridge endings,
bifurcations, dots, and combinations
Level 3:ridge detail
including pores
NOT sufficient for individualization, can be used for exclusion
sufficient for individualization
Fingerprints
Automated Fingerprint Identification System
AFISOperates by anchoring position of fingerprint and searching database using two types of ridges:•Bifurcations•Ridge endings
Database works by querying prints to find ones with same number of ridges in relative positionsMost likely matches are displayed for comparison by a fingerprint examiner
Which is more individualizing?
A. ridge endingB. loop
Identical twins have the same fingerprints.
A. TrueB. False
Do identical twins have the same DNA?
A. YesB. No
Old 10 print card
revised 10 print card